Download Testimony to the US Senate - Energy and Natural Resources

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Testimony to the US Senate - Energy and Natural Resources Committee
Sir John Houghton, 21 July 2005
I consider it a privilege to be asked to testify to your committee this morning. Thank
you for inviting me. On my last visit to the United States in March I was briefing the
National Association of Evangelicals and was most pleased to find that large and
influential body engaging with this issue of global climate change - the most serious
environmental issue facing the world today.
The basic science of global warming
Let me start with a quick summary of the basic science of Global Warming. By
absorbing infra-red or ‘heat’ radiation from the earth’s surface, ‘greenhouse gases’
present in the atmosphere, such as water vapour and carbon dioxide, act as blankets
over the earth’s surface, keeping it warmer than it would otherwise be. The existence
of this natural ‘greenhouse effect’ has been known for nearly two hundred years; it is
essential to the provision of our current climate to which ecosystems and we humans
have adapted.
Since the beginning of the industrial revolution around 1750, one of these greenhouse
gases, carbon dioxide has increased by over 30% and is now at a higher concentration
in the atmosphere than it has been for many hundreds of thousands of years (Fig 1).
Chemical analysis demonstrates that this increase is due largely to the burning of
fossil fuels - coal, oil and gas. If no action is taken to curb these emissions, the carbon
dioxide concentration will rise during the 21st century to two or three times its
preindustrial level.
Fig 1. Concentration of carbon dioxide in the atmosphere from 1000 AD and projected to 2100 under
typical IPCC scenarios1.
Fig 2. Variations of the average near surface air temperature: 1000-1861, N Hemisphere from proxy
data; 1861-2000, global instrumental; 2000-2100, under a range of IPCC projections with further
shading to indicate scientific uncertainty2.
The climate record over the last 1000 years (Fig 2) shows a lot of natural variability –
including, for instance, the ‘medieval warm period’ and the ‘little ice age’3. The rise
in global average temperature (and its rate of rise) during the 20th century is well
outside the range of known natural variability. The year 1998 is the warmest year in
the instrumental record. A more striking statistic is that each of the first 8 months of
1998 was the warmest on record for that month. There is strong evidence that most of
the warming over the last 50 years is due to the increase of greenhouse gases,
especially carbon dioxide. Confirmation of this is also provided by observations of the
warming of the oceans4. The period of ‘global dimming’ from about 1950 to 1970 is
most likely due to the increase in atmospheric particles (especially sulphates) from
1
From IPCC 2001 Synthesis Report published by Cambridge University Press 2001
From IPCC 2001 Synthesis Report published by Cambridge University Press 2001
3 Since the IPCC 2001 report there has been a debate in the scientific literature regarding the statistical procedures
for reconstruction of the proxy part of the record that might affect its overall shape especially over the 14 th to the
19th centuries (the little ice age period) –see for instance von Storch et al 2004, Science 306 621-2. This ‘hockeystick’ debate, however, does not significantly influence the main IPCC conclusions regarding the temperature of
the 20th century.
4 See recent paper by J Hansen et al in Sciencexpress for 28 April 2005 / 10.1126/science.1110252
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industrial sources. These particles reflect sunlight, hence tending to cool the surface
and mask some of the warming effect of greenhouse gases. Global climate models5
that include human induced effects (greenhouse gas increases and particles) and
known natural forcings (e.g. variations in solar radiation and the effects of volcanoes)
can provide good simulations of the twentieth century profile of global average
temperature change.
Over the 21st century the global average temperature is projected to rise by between 2
and 6 ºC (3.5 to 11 ºF) from its preindustrial level; the range represents different
assumptions about emissions of greenhouse gases and the sensitivity of the climate
model used in making the estimate (Fig 2). For global average temperature, a rise of
this amount is large. The difference between the middle of an ice age and the warm
periods in between is only about 5 or 6 ºC (9 to 11 ºF). So, associated with likely
warming in the 21st century will be a rate of change of climate equivalent to say, half
an ice age in less than 100 years – a larger rate of change than for at least 10,000
years. Adapting to this will be difficult for both humans and many ecosystems.
The impacts of human induced climate change
Talking in terms of changes of global average temperature, however, tells us rather
little about the impacts of global warming on human communities. Some of the most
obvious impacts will be due to the rise in sea level that occurs because ocean water
expands as it is heated. The projected rise is of the order of half a metre (20 inches) a
century and will continue for many centuries – to warm the deep oceans as well as the
surface waters takes a long time. This will cause large problems for human
communities living in low lying regions, for instance in the Everglades region of
Florida. Many areas, for instance in Bangladesh (where about 10 million live within
the one metre contour – Fig 3), southern China, islands in the Indian and Pacific
oceans and similar places elsewhere in the world, will be impossible to protect and
many millions will be displaced.
Fig 3. Land affected in Bangladesh by various amounts of sea level rise
There will also be impacts from extreme events. The extremely unusual high
temperatures in central Europe during the summer of 2003 led to the deaths of over
20,000 people. Careful analysis shows that it is very likely that a large part of the
cause of this event is due to increases in greenhouse gases and projects that such
summers are likely to be the norm by the middle of the 21st century and cool by the
year 2100.
Water is becoming an increasingly important resource. A warmer world will lead to
more evaporation of water from the surface, more water vapour in the atmosphere and
more precipitation on average. Of greater importance is the fact that the increased
condensation of water vapour in cloud formation leads to increased latent heat of
condensation being released. Since this latent heat release is the largest source of
energy driving the atmosphere’s circulation, the hydrological cycle will become more
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Global climate models run on large computers include all components of the climate system (atmosphere, land,
oceans, ice and biosphere) with global coverage, include algorithmic descriptions of all physical processes and
integrate the dynamical equations to provide simulations of current climate or projections of future climate. They
are powerful tools that add together the effects of all the non linear processes involved.
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intense. This means a tendency to more intense rainfall events and also less rainfall in
some semi-arid areas. Since, on average, floods and droughts are the most damaging
of the world’s disasters (see box), their greater frequency and intensity is bad news for
most human communities and especially for those regions such as south east Asia and
sub-Saharan Africa where such events already occur only too frequently.
BOX
Major floods in the 1990s
•1991, 1994-5, 1998 – China; average disaster cost 1989-96, 4% of GDP
•Mississipi & Missouri, USA; flooded area equal to one of great lakes
•1997 – Europe; 162,000 evacuated and > 5bn $ loss
•1998 - Hurricane Mitch in central America; 9000 deaths,
economic loss in Honduras &Nicaragua 70% & 45% of GDP
•1999 – Venezuela; flooding led to landslide, 30,000 deaths
•2000-1 - Mozambique; two floods leave more than half a million homeless
END OF BOX
Regarding extreme events and disasters, it is often pointed out that climate possesses
large natural variability and such events have been common occurrences over the
centuries. It is not possible, for instance, when a disaster occurs to attribute that
particular event to increasing greenhouse gases (except perhaps for the 2003 heat
wave mentioned above). So, what is the evidence that they will increase in a globally
warmed world? First, there is our understanding of the basic science of climate
change that I have briefly outlined. Secondly, increasing evidence is provided from
observations. Significant increases have been observed in the number of intense
rainfall events especially over areas like the USA where there is good data coverage.
Data from insurance companies show an increase in economic losses in weather
related disasters of a factor of 10 in real terms between the 1950s and the 1990s.
Some of this can be attributed to an increase in vulnerability to such disasters.
However, a significant part of the trend has also arisen from increased storminess
especially in the 1980s and 1990s.
Thirdly, increased risk of heat waves, floods and droughts are some of the most robust
projections of climate models that take into account in a comprehensive way all the
physical and dynamical processes involved in climate change. For instance, a study
for the area of central Europe, with doubled atmospheric carbon dioxide concentration
(likely to occur during the second half of the twenty first century), indicates an
decrease in the return period of flooding events by about a factor of five (e.g. from 50
years to 10 years)6.
Tropical cyclones are particular damaging storms that occur in the sub tropics. They
require special mention because no evidence exists for an increase in their number as
the earth warms although an increase is considered likely in peak wind and
precipitation intensities in such systems.
6
Palmer T N and Raisanen J, 2002, Nature, 415, 512-14
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Sea level rise, changes in water availability and extreme events will cause the most
damaging impacts of human induced climate change7. They will lead to increasing
pressure from many millions of environmental refugees.
In addition to the main impacts summarised above are changes about which there is
less certainty, but if they occurred would be highly damaging and possibly
irreversible. For instance, large changes are being observed in polar regions. If the
temperature rises more than about 3 ºC (~5 ºF) in the area of Greenland, it is
estimated that melt down of the ice cap would begin. Complete melt down is likely to
take 1000 years or more but it would add 7 metres (23 feet) to the sea level.
A further concern is regarding the Thermo-Haline Circulation (THC) – a circulation
in the deep oceans, partially sourced from water that has moved in the Gulf Stream
from the tropics to the region between Greenland and Scandanavia. Because of
evaporation on the way, the water is not only cold but salty, hence of higher density
than the surrounding water. It therefore tends to sink and provides the source for a
slow circulation at low levels that connects all the oceans together. This sinking
assists in maintaining the Gulf Stream itself. In a globally warmed world, increased
precipitation together with fresh water from melting ice will decrease the water’s
salinity making it less likely to sink. The circulation will therefore weaken and
possibly even cut off, leading to large regional changes of climate. All climate models
indicate the occurrence of this weakening. Evidence from paleoclimate history shows
that such cut-off has occurred at times in the past. It is such an event that is behind the
highly speculative happenings in the film, The day after tomorrow.
I have spoken so far about adverse impacts. However, there are some positive
impacts. For instance, in Siberia and other areas at high northern latitudes, winters
will be less cold and growing seasons will be longer. Also, increased concentrations
of carbon dioxide have a fertilising effect on some plants and crops which, providing
there are adequate supplies of water and nutrients, will lead to increased crop yields in
some places, probably most notably in northern mid latitudes. However, careful
studies demonstrate that adverse impacts will far outweigh positive effects, the more
so as temperatures rise more than 1 or 2 ºC (2 to 3.5 ºF) above preindustrial.
Many people ask how sure we are about the scientific story I have just presented. Let
me explain that it is based very largely on the extremely thorough work of the
Intergovernmental Panel on Climate Change (IPCC) and its last major report
published in 2001. The scientific literature on climate change has increased
enormously over the last decade. The basic science of anthropogenic climate change
has been confirmed. The main uncertainties lie in our knowledge of feedbacks in the
climate system especially those associated with the effects of clouds. Recent research
has tended to indicate increased likelihood of the more damaging impacts.
The Intergovernmental Panel on Climate Change (IPCC)
Let me explain more about the work of the IPCC. It was formed in 1988 jointly by the
World Meteorological Organisation and the United Nations Environment Programme.
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Many of the studies addressing the cost of global warming impacts fail to take account of the cost of extremes as
is explained in Houghton, Global Warming: the Complete Briefing, CUP 2004, chapter 7.
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I had the privilege of being chairman or co-chairman of the Panel’s scientific
assessment from 1988 to 2002. Hundreds of scientists drawn from many countries
were involved as contributors and reviewers in these assessments. The IPCC has
produced three assessments - in 1990, 1995 and 2001 – covering science, impacts and
analyses of policy options. The IPCC 2001 report is in four volumes each of about
1000 pages and containing many thousands of references to the scientific literature8.
Each chapter of the Report went through two major reviews, first by hundreds of
scientists in the scientific community (any scientist who wished could take part in
this) and secondly, by governments. No assessment on any other scientific topic has
been so thoroughly researched and reviewed.
Because the IPCC is an intergovernmental body, the reports’ Summaries for
Policymakers were agreed sentence by sentence by meetings in which governmental
delegates from about 100 countries (including all the world’s major countries) work
with around 40 leading scientists representing the scientific community. It is
sometimes supposed that the presence of governments implies political interference
with the process. That has not been the case. In any event, governments taking part
come from the complete spectrum of political agendas. These are scientific meetings
in which all proposals for changes in the text must be based either on scientific
arguments or on a desire for clearer presentation. In every case, the process has
resulted in documents with overall improved scientific clarity and balance.
The work of the IPCC is backed by the worldwide scientific community. A joint
statement of support was issued in May 2001 by the national science academies of
Australia, Belgium, Brazil, Canada, the Caribbean, China, France, Germany, India,
Indonesia, Ireland, Italy, Malaysia, New Zealand, Sweden and the UK. It stated ‘We
recognize the IPCC as the world’s most reliable source of information on climate
change and its causes, and we endorse its method of achieving consensus.’ In 2001, a
report of the United States National Academy of Sciences commissioned by the
President George W Bush administration, supported the IPCC’s conclusions9. A joint
statement issued in June 2005 by the science academies of all the G8 countries
together with the academies of Brazil, China and India also endorsed the work and
conclusions of the IPCC10.
Let me comment further on the issues of uncertainty and balance as expressed in the
work of the IPCC. There are very large amounts of data available to the scientist
looking for evidence of climate change. Examples abound of those who approach the
data with preconceived agendas and who have selected data to fit those agendas - for
instance purporting to prove either that there is little or no evidence for human
induced change or that the world is heading for a future that could mean the end of the
human race. The task of the IPCC has been to review all the evidence in a balanced
manner and honestly and objectively to distinguish what is reasonably well known
and understood from those areas with large uncertainty. The reports have
differentiated between degrees of uncertainty, where possible providing numerical
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Climate Change 2001 in four volumes, published for the IPCC by Cambridge University Press, 2001. Also
available on the IPCC web site www.ipcc.ch. My book, John Houghton, Global Warming: the complete briefing,
3rd edition, Cambridge University Press, 2004 is strongly based on the IPCC reports. Further a review I have
recently written (John Houghton, Global Warming, Reports Progress in Physics, 68 (2005) 1343-1403) provides a
concise summary of the science and associated impacts.
9
http://books.nap.edu/html/climatechange/
10 http://nationalacademies.org/morenews/
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estimates of uncertainty. A large part of the IPCC process, taking many days of
scientists’ time, has been taken up with discussion and correspondence about how
best to present uncertainty.
Let me mention a further point on the uncertainty issue. In the IPCC reports, because
they are scientific documents, uncertainty tends to be mentioned frequently giving the
impression to the casual reader that the uncertainty in the conclusions is larger than it
is in many other areas of our experience with which comparison could be made. What
is important to realise is that there is a high degree of certainty that significant human
induced climate change is occurring and will continue to occur. A forecast of little or
no such climate change is almost certainly wrong.
The Framework Convention on Climate Change
Because of the work of the IPCC and its first report in 1990, the Earth Summit at Rio
de Janeiro in 1992 could address the climate change issue and the action that needed
to be taken. The Framework Convention on Climate Change (FCCC) - agreed by over
160 countries, signed by President George Bush Snr for the USA and subsequently
ratified unanimously by the US Senate – agreed that Parties to the Convention should
take “precautionary measures to anticipate, prevent or minimise the causes of climate
change and mitigate its adverse effects. Where there are threats of irreversible
damage, lack of full scientific certainty should not be used as a reason for postponing
such measures.”
More particularly the Objective of the FCCC in its Article 2 is “to stabilise
greenhouse gas concentrations in the atmosphere at a level that does not cause
dangerous interference with the climate system” and that is consistent with
sustainable development. Such stabilisation would also eventually stop further climate
change. However, because of the long time that carbon dioxide resides in the
atmosphere, the lag in the response of the climate to changes in greenhouse gases
(largely because of the time taken for the ocean to warm), and the time taken for
appropriate human action to be agreed, the achievement of such stabilisation will take
at least the best part of a century.
Stabilization of carbon dioxide
Global emissions of carbon dioxide to the atmosphere from fossil fuel burning are
currently approaching 7 billion tonnes of carbon per annum and rising rapidly (Fig 4).
Unless strong measures are taken they will reach two or three times their present
levels during the 21st century and stabilisation of greenhouse gas concentrations or of
climate will be nowhere in sight. To stabilise carbon dioxide concentrations in
accordance with the FCCC Objective, emissions during the 21st century must reduce
to a fraction of their present levels before the century’s end.
The reductions in emissions must be made globally; all nations must take part.
However, there are very large differences between greenhouse gas emissions in
different countries. Expressed in tonnes of carbon per capita per annum, they vary
from about 5.5 for the USA, 2.2 for Europe, 0.7 for China and 0.2 for India (Fig 5).
Ways need to be found to achieve reductions that are both realistic and equitable.
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Fig 4. Global emissions of carbon dioxide from fossil fuel burning (in billions of tonnes of carbon) up
to 1990 and as projected to 2100 under World Energy Council scenarios 11, A’s and B’s with various
‘business as usual assumptions’ and C for ‘ecologically driven scenario’ that would lead to stabilisation
of carbon dioxide concentration at about 450 ppm.
Fig 5. Carbon dioxide emissions in 2000 per capita for different countries and groups of countries12.
The Kyoto Protocol set up by the FCCC represents a beginning for the process of
reduction, averaging about 5% below 1990 levels by 2012 by those developed
countries who have ratified the protocol. It is an important start demonstrating the
achievement of a useful measure of international agreement on such a complex issue.
It also introduces for the first time international trading of greenhouse gas emissions
so that reductions can be achieved in the most cost effective ways.
Serious discussion is now beginning about international agreements for emissions
reductions post Kyoto. These must include all major emitters in both developed and
developing countries. On what eventual level of stabilisation, of carbon dioxide for
instance, should these negotiations focus? To stop damaging climate change the level
needs to be as low as possible. In the light of the FCCC Objective it must also allow
for sustainable development. Let me give two examples of stabilisation proposals. In
1996 the European Commission proposed a limit for the rise in global average
temperature from its preindustrial value of 2 ºC – that implies a stabilisation level for
carbon dioxide of about 430 ppm (allowing for the effect of other greenhouse gases at
their 1990 levels). The second example comes from Lord John Browne, Chief
Executive Officer of British Petroleum, one of the world’s largest oil companies, who
in a recent speech proposed 'stabilisation in the range 500-550 ppm' that 'with care
could be achieved without disrupting economic growth.'
Let us consider carbon dioxide stabilisation at 500 ppm. If the effect of other
greenhouse gases at their 1990 levels is added, it is about equivalent to doubled
carbon dioxide at its preindustrial level and a rise in global averaged temperature of
about 2.5 ºC. Although climate change would eventually largely be halted – although
not for well over a hundred years - the climate change impacts at such a level would
be large. A steady rise in sea level will continue for many centuries, heat waves such
as in Europe in 2003 would be commonplace, devastating floods and droughts would
be much more common in many places and Greenland would most likely start to melt
down. The aim should be therefore to stabilise at a lower level. But is that possible?
The International Energy Agency (IEA) in 2004 published a World Energy Outlook
that in their words ‘paints a sobering picture of how the global energy system is likely
to evolve from now to 2030’. With present governments’ policies, the world’s energy
needs will be almost 60% higher in 2030 that they are now. Fossil fuels will
dominate, meeting most of the increase in overall energy use. Energy-related
emissions of carbon dioxide will grow marginally faster than energy use and will be
more than 60% higher in 2030 than now (Fig 6, reference scenario). Over two-thirds
of the projected increase in emissions will come from developing countries.
From Energy for Tomorrow’s World: the realities, the real options and the agenda for achievement. World
Energy Council Report 1993
12 After M Grubb 2003, World Economics 3, p 145
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Fig 6. Carbon dioxide emissions from fossil fuel burning and profile leading to stabilisation at 500 ppm
(a, b and c) and 450 ppm (d). Emissions data from International Energy Agency scenarios 13; reference
(a), alternative (b) for developed countries (red) and developing (blue). For (c) and (d) see text.
The Outlook also presents an Alternative Scenario that analyses the global impact of
environmental and energy-security policies that countries around the world are
already considering as well as the effects of faster deployment of energy-efficient
technologies. However, even in this scenario, global emissions in 2030 are
substantially greater than they are today (Fig 6). Neither scenario comes close to
creating the turn around in the global profile required.
The UK government has taken a lead on this issue and has agreed a target for the
reduction of greenhouse gas emissions of 60% by 2050 - predicated on a stabilisation
target of doubled carbon dioxide concentrations together with a recognition that
developed countries will need to make greater reductions to allow some headroom for
developing countries. Economists in the UK government Treasury Department have
estimated the cost to the UK economy of achieving this target. On the assumption of
an average growth in the UK economy of 2.25 % p.a., they estimated a cost of no
more than the equivalent of 6 months’ growth over the 50 year period. Similar costs
for achieving stabilisation have been estimated by the IPCC.
The effect of a reduction of 60% on average by developed countries is shown in Fig
6(c) together with a scenario for developing countries that increases by 1% p.a. until
2030 followed by level emissions to 2050. For this the 500 ppm curve is
approximately followed but for developing countries to be satisfied with such a
modest growth presents a very large challenge. Even more challenging for both
developed and developing countries would be the measures required to stabilise at
450 ppm (Fig 6(d). Governor Schwarzenegger of California has begun to address this
challenge by proposing an even more demanding reduction target of 80% by 2050.
Can we wait and see?
In order to achieve reductions on the scale that is required to stabilize carbon dioxide
concentrations, large changes will have to occur in way we use energy (through
energy efficiency improvements) and generate it (through moves to energy sources
with zero or low carbon emissions). But how urgent are the changes required. It is
sometimes suggested that we can ‘wait and see’ before serious action is needed. This
is an area where policy needs to be informed by the perspective from science.
There is a strong scientific reason for urgent action. Because the oceans take time to
warm, there is a lag in the response of climate to increasing greenhouse gases. So far
we have only experienced a small part of the climate response to the greenhouse gas
emissions that have already occurred. If greenhouse gas emissions were halted
tomorrow, climate impacts much greater than we have so far experienced but to
which we are already committed will be realized over the next 30 years and more into
the future14. Further emissions from now on just add to that commitment. It is for this
reason that the June 2005 statement from the world’s major science academies urges
all nations15, ‘to take prompt action to reduce the causes of climate change and adapt
13
From World Energy Outlook, IEA 2004
see recent paper by J Hansen et al in Sciencexpress for 28 April 2005 / 10.1126/science.1110252
15 http://nationalacademies.org/morenews/
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to its impacts’ and to ‘identify cost-effective steps that can be taken now to contribute
to substantial and long-term reduction in net global greenhouse gas emissions,
recognizing that delayed action will increase the risk of adverse environmental effects
and will likely incur a greater cost.’
Two further reasons can be identified for urgent action. One is economic. Energy
infrastructure, for instance in power stations also lasts typically for 30 to 50 years. As
was stated by the leaders of the G8 countries meeting at Gleneagles in the UK earlier
this month16, We face a moment of opportunity. Over the next 25 years, an estimated
$16 trillion will need to be invested in the world’s energy systems. According to the
IEA, there are significant opportunities to invest this capital cost-effectively in
cleaner energy technologies and energy efficiency. Because decisions being taken
today could lock in investment and increase emissions for decades to come, it is
important to act wisely now.
A third reason is political. Countries like China and India are industrialising very
rapidly. I heard a senior energy adviser to the Chinese government speak recently. He
said that China by itself would not be making big moves to non fossil fuel sources.
When the developed nations of the west take action, they will take action - they will
follow not lead. China is building new electricity generating capacity of about 1 GW
power station per week. To move the world forward we have to be seen ourselves to
be moving.
The UK and Climate Change
I would like to add a few remarks about the UK and climate change. It was Prime
Minister Margaret Thatcher who in 1988, speaking as a scientist as well as a political
leader, was one of the first to bring the potential threat of global warming to world
attention. Subsequent UK governments have continued to play a leading international
role in this issue. This year, Prime Minister Tony Blair has put climate change at the
top of his agenda for his presidency of the G8 and the EU.
This international activity has brought the realisation within the UK government that
a big environmental issue such as climate change needs to be brought much closer to
the centre of the government machine. For instance, Gordon Brown, UK’s
Chancellor of the Exchequer has clearly stated the importance of addressing the
economy and environment together. In a recent speech he said17, ‘Environmental
issues - including climate change – have traditionally been placed in a category
separate from the economy and from economic policy. But this is no longer tenable.
Across a range of environmental issues –from soil erosion to the depletion of marine
stocks, from water scarcity to air pollution – it is clear now not just that economic
activity is their cause, but that these problems in themselves threaten future economic
activity and growth.’
16
http://www.g8.gov.uk
address to the Energy and Environment Ministerial Roundtable, 15 March 2005;
http://www.hm-treasury.gov.uk/newsroom_and_speeches/press/2005/press_29_05.cfm
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The need for leadership
We, in the developed countries have already benefited over many generations from
abundant and cheap fossil fuel energy – although without realising the potential
damage to the climate and especially the disproportionate adverse impacts falling on
the poorer nations. The Framework Convention on Climate Change (FCCC)
recognized the particular responsibilities this placed on developed countries to be the
first to take action and to provide assistance (e.g. through appropriate finance and
technology transfer) to developing countries for them to cope with the impacts and to
develop cost effective sources of energy free of carbon emissions. The moral
imperative created by these responsibilities is reflected in the statement on climate
change made by the leaders of the G8 countries meeting at Gleneagles in the
following paragraph18, ‘It is in our global interests to work together, and in
partnership with major emerging economies, to find ways to achieve substantial
reductions in greenhouse gas emissions and our other key objectives, including the
promotion of low-emitting energy systems. The world’s developed economies have a
responsibility to act.’
People often say to me that I am wasting my time talking about Global Warming.
‘The world’ they say ‘will never agree to take the necessary action’. I reply that I am
optimistic for three reasons. First, I have experienced the commitment of the world
scientific community (including scientists from many different nations, backgrounds
and cultures) in painstakingly and honestly working together to understand the
problems and assessing what needs to be done. Secondly, I believe the necessary
technology is available for achieving satisfactory solutions. My third reason is that, as
a Christian, I believe God is committed to his creation and that we have a God-given
task of being good stewards of creation – a task that we do not have to accomplish on
our own because God is there to help us with it. As a recent statement on climate
change by scientific and religious leaders in the U.S. says19: ‘What is most required at
this moment … is moral vision and leadership. Resources of human character and
spirit – love of life, far sightedness, solidarity – are needed to awaken a sufficient
sense of urgency and resolve.’
In my work with the IPCC I have been privileged to work with many climate
scientists from the USA who are world leaders in their field. The USA is also a world
leader in the technologies aimed at reducing greenhouse gas emissions. But science
and technology are only part of what is required. Mr Chairman, the moves recently
made by the Senate to develop a strategy for addressing the issue of human induced
climate change are of great importance. Is it too much to hope that they are the start of
a bid for leadership by the US in the wider world as all countries - both developed and
developing – set out to meet this challenge together?
Sir John Houghton was co-chairman of the Scientific Assessment for the IPCC from 1988-2002. He
was previously chairman of the Royal Commission on Environmental Pollution (1992-1998), Chief
Executive of the UK Meteorological Office (1983-1991) and Professor of Atmospheric Physics,
University of Oxford (1976-1983). He is currently chairman of the John Ray Initiative, a Trustee of the
Shell Foundation and Honorary Scientist at the Hadley Centre.
18
http://www.g8.gov.uk
From Earth’s Climate Embraces Us All: A Plea From Religion and Science for Action on Global Climate
Change, July 2004; available form the National Religious partnership for the Environment at
http://www.nrpe.org/climate_letter.pdf
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Captions to Figures
Fig 1. Concentration of carbon dioxide in the atmosphere from 1000 AD and projected to 2100 under
typical IPCC scenarios20.
Fig 2. Variations of the average near surface air temperature: 1000-1861, N Hemisphere from proxy
data; 1861-2000, global instrumental; 2000-2100, under a range of IPCC projections with further
shading to indicate scientific uncertainty21.
Fig 3. Land affected in Bangladesh by various amounts of sea level rise.
Fig 4. Global emissions of carbon dioxide from fossil fuel burning (in billions of tonnes of carbon) up
to 1990 and as projected to 2100 under World Energy Council scenarios 22, A’s and B’s with various
‘business as usual assumptions’ and C for ‘ecologically driven scenario’ that would lead to stabilisation
of carbon dioxide concentration at about 450 ppm.
Fig 5. Carbon dioxide emissions in 2000 per capita for different countries and groups of countries23.
Fig 6. Carbon dioxide emissions from fossil fuel burning and profile leading to stabilisation at 500 ppm
(a, b and c) and 450 ppm (d). Emissions data from International Energy Agency scenarios 24; reference
(a), alternative (b) for developed countries (red) and developing (blue). For (c) and (d) see text.
20
From IPCC 2001 Synthesis Report published by Cambridge University Press 2001
From IPCC 2001 Synthesis Report published by Cambridge University Press 2001
22 From Energy for Tomorrow’s World: the realities, the real options and the agenda for achievement. World
Energy Council Report 1993
23
After M Grubb 2003, World Economics 3, p 145
24 From World Energy Outlook, IEA 2004
21